Flexible articles have been disclosed which comprise a fabric having a plasticized PVC layer secured to each side of the fabric. These articles have been shown to demonstrate relatively good flex-crack resistance--a property that relates to the articles ability to withstand repeated flexing at ambient temperatures, particularly low ambient temperatures. Flexible PVC-containing articles also have demonstrated good resistance to weathering, have exhibited an ability to be easily colored throughout the polymer, and an ability to be inked on the outer surface. These properties, coupled with the relative low cost of PVC, have promoted the widespread use of flexible PVC-containing articles. Some of the many utilities for flexible PVC-containing articles include a fitted cover dimensioned for use on a truck or truck trailer, outdoor banners, awnings, upholstering, and a backing for a retroreflective roll-up sign (see e.g. U.S. Pat. No. 5,175,646). Although the flexible PVC-containing articles have gained tremendous widespread use, from an environmental standpoint these articles may not be so desirable.
As landfill sites are becoming less common, there is a greater tendency to dispose of articles that contain PVC through incineration. The incineration of PVC can produce hydrochloric acid. It is feared that the hydrochloric acid enters the atmosphere and produces acid rain. It also is feared that dioxins and furans are liberated when PVC is burned at municipal incinerators. Discussions are underway in many nations to ban PVC because of its potentially harmful effect on the environment. See generally K. Kreisher, PVC is a Good Bet to Survive its Global Environmental Travails, Modern Plastics 60-64 (June 1990); The Ministry of Environmental Protection Letter of 20.10. 1988 to the Danish Parliament's Environmental Committee; and E. Chynoweth et al., Green Pressures Force PVC to Take LCA Lead in Europe, Chemical Week 41-42 (Nov. 18, 1992).
In addition to its environmental problems, flexible PVC-containing articles also pose the problem of having a low molecular weight plasticizer migrate to the surface of the PVC layer. The PVC layer typically contains a low molecular weight plasticizer to impart flexibility to the layer over a wide range of temperatures. This plasticizer is fairly mobile in the PVC layer and usually migrates out of the article, leaving it with a semi-tacky outer surface onto which dirt and other particles can adhere. The migration of the plasticizer also can cause the PVC article to be less flexible, it can allow the plasticizer to enter other articles that are adjacent to the PVC article, and it can interfere with the application of an ink on the surface of the article. Further, the most common plasticizer for flexible PVC is carcinogenic to laboratory animals, although a direct link to humans has not been proved. See supra Kreisher at 60. Although high molecular weight plasticizers may be used, which do not migrate out from the interior of the PVC layer, these plasticizers do not impart good flex crack resistance to the PVC-containing article.
Articles are known which comprise fabrics secured to polymeric layers that contain polymers other than PVC. Examples of such articles have been disclosed in the following documents: U.S. Pat. Nos. 4,844,958, 4,636,427, 4,531,994, 4,471,018, 4,351,876, 3,125,462, 2,299,807; EP-A 0,399,439 A2; and Japanese Patent Kokoku 60-52950. None of these documents, however, disclose that their articles demonstrate good flex-crack resistance so as to be a suitable alternative for a plasticized, PVC-containing article. In U.S. Pat. No. 3,703,779 a translucent card is disclosed that comprises a piece of paper laminated between two sheets Of plastic. Each plastic sheet includes two polymeric layers, an inner layer of polyethylene and an outer layer of polyester. It is doubtful that this laminated article is very flexible or that it has good flex-crack resistance or good tear strength because it employs a piece of paper for the central structural layer.
Roll-up signs are well known in the outdoor display and traffic control materials art. These signs are portable and can be folded or rolled up for transport and storage until being used again in a non-rolled up or extended condition. Examples of roll-up signs are shown in U.S. Pat. Nos. 5,175,646, 5,016,372, 4,999,938, 4,980,984, 4,694,601, 4,592,158, 4,490,934, and UK Patent Application GB 2,247,859 A. The signs typically comprise a retroreflective layer having an indicia on the front side and a PVC coated fabric on the back side. In U.S. Pat. No. 5,016,372, a roll-up sign is disclosed that is made of polyethylene plastic.